Method of making luminous signs



I July 1942. F. w. TEMPLE 2,289,084

METHOD OF MAKING LUMINOUS SIGNS Filed April 9, 1941 v I v "IIIIIIIIIIIIIIIIIIIIIIIIA Patented July-i, 1942 UNITED STATES PATENT OFFICE METHOD OF MAKING LUMINOUS SIGNS Fred W. Temple, La Crosse, Wis.

Application April 9, 1941, Serial No. 387,632

4 Claims.

This invention relates to an improved form of luminous character signs and the method of producing the improved signs. The method is disclosed in part in my co-pending application Serial No. 387,630, filed April 9, 1941, in which co-pending application the method is claimed so far as it is there disclosed. The apparatus for carrying out the method is also disclosed and claimed in part in said co-pendingapplication.

The sign formingthe subject matter of this application comprises a combination of thermoplastic material witha layer of paint, ink, or other covering material thereon at a portion of its face, such paint or other covering material being arranged preferably for blocking the passage of light through the sign and either providing additional sign subject matter or not as may be desired.

The improved method of producing one preferred form of sign as shown by the drawing comprises the step or steps of applying a layer of paint or other suitable covering material by a printing operation or otherwise upon one face of a flat straight piece of translucent thermoplastic material of any desired color, leaving a portion of the face free of the covering material so as to show the outline of a design. After the printing of the thermoplastic sheet in its original fiat condition, the sheet is placed in a suitable mold adjacent to a die plate having recesses shaped to correspond with the design, after which pressure and heat are applied on the face of the plastic sheet for softening the plastic material and forcing it outwardly into the recesses of the die plate so as to form block letters or other characters. It has, been found that block letters can be formed in this manner by the use of heat and the letters can be set in their changed ofiset form without in any way objectionably affecting the layer of covering material surrounding the portions of the plastic sheet which are offset for the formation of the letters or other design.

It is anotherobject of this invention to improve signs of this type and the method of producing them in sundry details hereinafter pointed out. The preferred means by which the several objects are attained are illustrated in the accompanying drawing, in which- Fig. 1 is a face view of a piece of thermoplastic material covered with a layer of paint or the like, with a design in the form of a series of letters within the outline of which the paint is omitted, the drawing showing the paint removed at one corner of the sheet;

Fig. 2 is an enlarged detail, being a sectional view taken on an enlarged scale at the line 22 of Fig. 1; I

Fig. 3 is a view similar to Fig. 1 but with the letters expanded into their block form;

Fig. 4 is an enlarged detail, being a sectional view taken on an enlarged scale at the line 4-4 of Fig. 3; and

Fig. 5 is a central sectional view through a mold of the type by which the sign as shown in Fig. 3 may be formed.

Referring now to the several figures of the drawing, in which corresponding parts are indicated by the same reference characters, Ill indicates a sheet of thermoplastic material having a layer ll of paint thereon at the greater portion of the face of the sheet but with portions of the sheet left uncovered so as to show a design by contrast with the covered portions. In the arrangement shown in Fig. 1, the design comprises a plurality of letters I2 making up the word Peerless." In the arrangement shown, the sheet ID or the layer of paint ll carries additional sign subject matter comprising the word Cooling at l3 and the word Refreshing" at H, such words being printed in contrasting color or form so as to be readily legible upon the background provided by the layer of paint I I.

is carried on from the stage as illustrated in Fig.

1 is quite similar to the apparatus shown in my above mentioned copending application. This mold comprises a heavy plate l5 supporting a frame l6 and a sealing'strip ll of rubber with a rubber blanket l8 supported by the plate IS with its edge portions spread over the frame l8 and the strip ll. An inlet pipe l9 arranged with a, bailie plate 20 is provided for feeding hot and cold water alternatively into the mold, and an outlet pipe 2| arranged with a baflle plate 22 is provided for controlling the movement of water out of the mold, the pipes I9 and 2| having suitable shut-off valves as shown in said prior application. Above the rubber blanket l8, one of the sheets l0-of thermoplastic material is placed in the position as shown in Fig. 1, with the layer of paint H preferably on top. Above the sheet I 0, I have provided a suitable die member 23, above which in turn there is a top plate 24 pro vided with a pressure block 25 thereon for the application of pressure upon the mold, preferably by the use of such means as that shown and described in said prior application.

As shown in Fig. 5, the die member 23 is provided with a plurality of recesses 16 in its bottom face corresponding in shape to the outline of the sign to be formed. In the arrangement illustrated, the recesses 25 correspond to the letters I! making up the word "Peerless as above described. The die 23 is of sufficient thickness for accommodating the depth of recesses 26 desired with an additional thickness of material above the recesses, so that the single die 23 serves to limit the movement of the plastic material of the sheet l into offset relation for forming the letters in relief.

After the sheet ID has been prepared in the condition as shown in Fig. 1 and has been placed in position in the mold as shown in Fig. 5, heat and pressure are applied upon the thermoplastic sheet it through the medium of hot water or other liquid introduced through the pipe is under suitable continued pressure. As the thermoplastic material softens, the sheet material is offset upwardly into the recesses 26 which are connected with the atmosphere so as to permit the air to escape. In this operation, the thermoplastic material is drawn out into thinner sheet portions, as is shown in Fig. 4, so as to produce offset letters 21 corresponding in shape to that of the letters I2, as shown in Fig. 1. After the thermoplastic material has been fully offset as controlled by the die member 23, the mold and its contents are cooled by the admission of cooler water to take the place of the hot water initially employed, this being effected under substantially the same pressure conditions as those initially obtaining.

I have found that the expansion of the thermoplastic material into the offset form as shown in Fig. 4 for providing the design as shown in Fig. 3 is effected without objectionally affecting the layer ll of paint or the additional sign material at I 3 and [4. The result is that in the final product the spaces between the letters making up the offset portion of the sign are effectively covered by the paint II. In one preferred form of the sign, the covering material I I of paint or other paint-like material is of such character as to make the major portion of the completed sign substantially opaque so as to be in marked contrast with the offset design portion which is preferably translucent.

By my improved method, I am enabled to make a highly effective sign at an exceedingly low cost. The work of making the sign can be done to advantage by any skilled worker, it being understood that the die member 23 might be formed of a plurality of connected parts rather than in the integral form as shown in Fig. 5 of the drawing.

The sign in its complete form, comprising a box for enclosingthe source of light, can be made very light so as to enable the sign easily to be erected and maintained. The source of light may be an ordinary incandescent lamp energized by the usual commercial volt current without the necessity for a transformer or other special equipment.

While I prefer to employ the form and arrangement of parts as shown in my drawing and as above described, the invention is not limited thereto except so far as the claims may be so limited, it being understood that changes might well be made in the form and arrangement without departing from the invention.

I claim:

1. The method of making a luminous character sign, comprising covering a portion only of the face of a sheet of thermoplastic material with a layer of covering material adapted to set in bonding relation to the sheet and arranged to show a selected design by contrast with the portion uncovered, and app g heat and pressure at the portion of the sheet not covered by said setting material so as'to displace the plastic material for showing the design in offset relation to the body of the sheet.

2. The method of making a luminous character sign, comprising covering the major portion of the face of a sheet of translucent thermoplastic material with a layer of paint adapted to dry in bonding relation to the sheet and arranged so that the outline of the uncovered portions corresponds with a selected design, and then applying heat and pressure at the portions of the sheet not covered by said paint so as to displace the plastic material for producing the design in relief.

3. The method of making a luminous character sign, comprising covering a portion of the face of a sheet of thermoplastic material with a layer of covering material adapted to set in bonding relation to the sheet and arranged so that the outline of the uncovered portions corresponds with a selected design, printing additional sign subject matter on said covered portion of the sheet, and then applying heat and pressure at the portions of the sheet not covered by said setting material so as to displace the plastic material for showing the design in relief.

4. The method of making a luminous character sign, comprising covering a portion only of the face of a sheet of translucent thermoplastic material with a layer of covering material adapted to set in bonding relation to the sheet and adapted substantially to prevent the passage of light through the covered portion of the sheet and arranged to show a selected design by contrast with the portion left uncovered, and applying heat and pressure at the portion of the sheet not covered by said setting material so as to displace the plastic material for showing the design in offset relation to the body of the sheet.

FRED W. TEMPLE. 

